The present invention relates to composites useful in building structures such as floor tiles, pavers, flagstones, etc., and methods of preparing the same.
The existing processes to polymer coat or glaze Portland cement based structures are performed using cured Portland cement based structures as inserts or finished components. In other words, prior to polymer coating, glazing or painting masonry on concrete surfaces, the Portland cement based structures are in an advanced stage of cure, i.e., the concrete structures are well aged or heat processed to the point where they are easily handled.
The conventional method of glazing concrete structures is to apply the highly filled polyester or epoxy material on Portland cement based structures produced by dry casting the material. In this process, the water to cement ratio (w/c) is minimized by tumbling the aggregates with closely controlled amounts of water and applying pressure to consolidate the damp vibrated mix even further. These dry cast blocks are often glazed with a thermoset polymer after xcx9c24 hrs of initial consolidation. Other processes for decorating cured concrete areas include painting with moisture or air cured materials, spraying freshly mixed two component systems normally followed by a post cure and xe2x80x9cbroadcastxe2x80x9d whereby freshly mixed unsaturated polyester or epoxy is rolled onto cured (mud, in some cases newly hardened and damp) floors followed by broadcasting colored sand and quartz into the polymer, letting it cure and sweeping away the excess mineral.
Thus, the bonding between the coating and the concrete surface using these conventional processes is basically chemical in nature. The composite of the present invention has a bond between the thick coating or glaze and the concrete structure which is superior in strength to the conventional composites, since the bond is not only chemical, but is strongly mechanical in nature consisting of numerous mechanisms, many of which are not available to the above decorative techniques. The present method provides a mechanism for forming a substantially thick transitional layer between the polymeric coating and the concrete structure which comprises three dimensional structures (herein alternatively referred to as Locks xe2x80x9cLxe2x80x9d or pockets) that act to mechanically hold the layers together, thereby forming a strong bond between the coating and the concrete which is both chemical and mechanical in nature.
The present Inventor is not aware of any process for the preparation of a composite tile wherein freshly mixed organic and inorganic based materials are sequentially deposited at a point when the curing process has either not been initiated or has just been initiated. This method results in a multitude of bonding mechanisms between the components and provides for excellent adhesion between very dissimilar materials. The composite tile is economically advantageous due to the lower cost of the requisite raw materials and has the advantage in that the processing sequence is easily scaled to millions of units per year using either a multi station conveyor or automated carousel equipment.
Additionally, the present Inventor is not aware of ultraviolet light-curable materials being used on finished precast blocks or dry cast structures.
An object of the present invention is to combine thermoset and/or ultraviolet light curable thermoset polymers with complex fillers and concrete technologies to provide novel methods to produce low cost, functional designs of floor tiles and many other building products to provide limitless colors, styles and textures for both indoor and outdoor use.
Another object of the present invention is to prepare a composite having a cementitious backing with a polymeric coating having a strong bond therebetween.
And yet another object of the present invention is to dramatically reduce the time for preparation of the floor tile or other building structure composite by using ultraviolet light-curable materials with finished precast blocks.
The composite structure of the present invention is suitable for a wide range of building products and comprises:
a first layer of solid particles intimately mixed with a polymeric binder;
a second layer of an organic and/or inorganic solid; and
optionally a transitional layer located between the first and second layers comprising both the polymeric binder and the organic and/or inorganic solids wherein the polymeric binder is contained in pockets within the organic and/or inorganic solid and at least some of the pockets of the polymeric binder extend from the first layer;
with the proviso that the transitional layer must be present unless the organic and/or inorganic solid is a cast structure having a smooth surface and the polymeric binder is curable with ultraviolet radiation; and
with the additional proviso that when the organic and/or inorganic solid is a cast structure, then the polymeric binder is curable with ultraviolet radiation.
The tile or building structure will ultimately be positioned so that the first layer of the solid particles mixed with a polymeric binder forms the decorative surface. The surface connected pockets or locks of the polymeric binder within the transitional layer result from combining the backing material when it is in the form of a slurry, paste or liquid with the filled polymerizing or polymerizable solution used to prepare the decorative polymeric binder of the surface layer, wherein the organic and/or inorganic slurry, paste or liquid is chosen to have a higher specific gravity than the polymerizable solution which is deposited first.
Additionally, the composite structure may have a third layer of a cured polymer resin which is in contact with at least one of the first, second or transitional layers,
wherein the third layer has a color different from the first layer.
In an alternative embodiment of the present invention, the composite structure may be prepared using a mold, having at least a bottom plate of the mold, prepared from quartz, which is substantially transparent to ultraviolet radiation. A UV curable filled polymeric binder is first prepared in the mold, and then a backing material is placed on the filled polymeric binder. Curing of the polymeric binder in the mold, is engendered by shining the ultraviolet radiation upward through the quartz plate.
The composite structure of the present invention having a transitional layer is prepared by a method, comprising:
combining a first polymerizable solution with first solid particles, which may be a blend of two or more types of solid particles,
settling the first solid particles in the first polymerizable solution thereby forming a first layer,
wherein the amount of the first polymerizable solution used is sufficient to at least submerge all of the first solid particles after the settling step,
contacting a slurry, paste or liquid with the surface of the first polymerizable solution,
wherein the slurry, paste or liquid has a higher specific gravity than the first polymerizable solution,
allowing the first polymerizable solution to migrate into the slurry, paste or liquid to form pockets of the first polymerizable solution in the slurry, paste or liquid, wherein at least some of the pockets remain connected to the first layer;
curing the first polymerizable solution.
The composite structure of the present invention using ultraviolet light-curable polymers is prepared by a method, comprising:
combining a first polymerizable solution with first solid particles,
settling the first solid particles in the first polymerizable solution,
wherein the amount of the first polymerizable solution used is sufficient to at least submerge all of the first solid particles after the settling step,
contacting the surface of the first polymerizable solution with a cast structure,
curing the first polymerizable solution with ultraviolet radiation to form a polymeric binder which acts as the composite structure""s surface.
These methods may be performed in a mold having a bottom wall connected to side walls, wherein the bottom wall has at least one raised configuration. In the cure where the UV curing is employed, the bottom wall is made of quartz. This mold is ideal for preparing a composite structure having three dimensional imprints. Additionally, the imprints can be prepared of a different color than the flat surface of the composite by applying (preferably by spraying) a colored solution of a second polymerizable solution to the at least one raised configuration before adding the first filled polymerizable solution.
Also envisioned, is to have a clear gel coat sprayed into the mold may precede the process.